Table 2

Prognostic value of clinical, radiographic, molecular and MRI-based risk factors: mean values and variability in knees with radiographic osteoarthritis (ROA) which displayed no change in cartilage thickness (no progression) vs those which displayed cartilage thinning over 24 months

	ROA no change (n=45)		ROA thinning (n=19)
Risk factor	Mean	SD	Mean	SD	Percentage difference	AUC (ROC)	p Value (Wilcoxon)
Age (years)	58.4	8.1	58.7	9.1	0.6	0.503	0.9941
BMI (kg/m2)	33.7	6.6	37.1	6.4	10.2	0.621	0.1310
WOMAC_pain	5.07	3.93	6.79	3.92	34.0	0.630	0.1076
WOMAC_stiffness	2.40	1.67	3.74	2.18	55.7	0.680	0.0223
WOMAC_function	16.73	13.91	26.00	14.89	55.4	0.677	0.0212
OP_score_MT	0.71	0.59	0.89	0.66	25.8	0.567	0.4625
OP_score_cMF	0.18	0.65	0.79	1.18	344.1	0.637	0.0163
JSN_score_MFTC	0.64	0.68	1.47	0.77	128.7	0.741	*0.0001*
mJSW (mm)	4.03	0.88	3.17	0.99	−21.4	0.738	*0.0035*
Anat. alignm. axis (°)	181.3	2.4	178.8	2.5	−1.4	0.767	*0.0012*
ln sIntactPINP	3.69	0.37	3.55	0.63	−3.8	0.617	0.1877
ln sCTXI	−1.36	0.64	−1.67	0.78	−22.7	0.654	0.0441
ln pNPII	0.46	0.90	0.88	1.01	92.9	0.642	0.1013
ln uTINE_Cr	3.18	0.69	3.25	0.70	2.2	0.552	0.5010
ln sCPII	5.87	0.36	5.85	0.30	−0.4	0.526	0.7133
ln sPIIANP	6.60	0.75	6.53	0.66	−1.1	0.523	0.9349
ln uCTXII_Cr	5.35	0.59	5.41	0.46	1.1	0.546	0.6088
ln uARGS_Cr	−0.78	0.71	−0.77	1.08	1.3	0.515	0.8672
ln sCOMP	2.36	0.28	2.33	0.29	−1.0	0.516	0.9531
ln uTIINE_Cr	4.46	0.61	4.48	0.67	0.4	0.528	0.7231
ln p15HETE	5.63	0.62	5.62	0.63	−0.2	0.489	0.8890
ln pPGE₂	3.75	0.95	3.84	0.77	2.3	0.492	1.0000
ln uOsteop_Cr	1.31	1.10	1.22	1.24	−7.5	0.484	0.8882
ln sPIIINP	1.32	0.34	1.21	0.33	−8.0	0.557	0.3977
ln uTIIINE_Cr	5.45	0.71	5.44	0.76	−0.3	0.475	0.7309
ln p3-NT	7.25	0.40	7.25	0.51	0.0	0.470	0.7842
Menisc_height (mm)	0.25	0.12	0.23	0.12	−8.3	0.515	0.8017
Menisc_sublux (mm)	0.42	0.17	0.48	0.14	14.7	0.630	0.0962
Meniscus_%Cover	12.93	8.60	9.31	6.35	−28.0	0.578	0.1759
ThCtAB_MT (mm)	1.67	0.19	1.62	0.21	−3.1	0.568	0.4223
ThCtAB_cMF (mm)	1.80	0.24	1.46	0.32	−18.8	0.805	*0.0001*
dGEMRIC_Me_MT	498.51	88.71	456.17	100.67	−8.5	0.684	0.0193
dGEMRIC_Me_cMF	551.45	99.99	517.69	113.27	−6.1	0.617	0.1064
dGEMRIC_SD_MT	105.48	36.33	108.25	38.79	2.6	0.545	0.8384
dGEMRIC_SD_cMF	126.62	40.79	137.84	38.38	8.9	0.592	0.2603
T2_Me_MT	46.23	6.52	47.44	3.00	2.6	0.591	0.2996
T2_Me_cMF	54.92	8.39	53.48	6.93	−2.6	0.560	0.5697
T2_SD_MT	16.10	2.97	17.78	2.18	10.4	0.658	0.0705
T2_SD_cMF	17.64	3.39	18.15	2.45	2.8	0.563	0.6306

The table reports bivariate analyses (progression vs no progression) without adjustment for other factors.
p Value, level of significance of differences between ROA knees with cartilage thinning vs those without significant change, determined using the Wilcoxon Rank Sum test (Fisher Exact test was used for ordinal variables, ie, OP and JSN scores). A p value given bold and in italics was significant at p<0.05 after correction for multiple testing using false discover rates (FDR); a p value given in italics was significant at p<0.05 before, but not after correction for multiple testing
anat. alignment axis, anatomical knee axis determined from the Lyon Schuss (LS) radiographs (note there is an approximate 4° offset with the mechanical knee axis, ie, 184° is considered neutral alignment); BMI, body mass index; cMF, medial weightbearing femur; dGEMRIC, delayed gadolinium-enhanced MRI; MFTC, medial femorotibial compartment; menisc. height, meniscal height; menisc. Sublux, meniscal subluxation; Menisc_%Cover, percentage of tibial plateau covered by meniscus; mJSW, minimal joint space width measured quantitatively in LS radiographs; molecular markers (ln, natural logarithmic transformation) from urine (u), plasma (p), or serum (s): sIntactPINP, (intact) N-terminal propeptide of type I procollagen (μg/l); MT, medial tibia; OP, ordinal osteophyte scores (range 0–3) and JSN, ordinal joint space narrowing scores (range 0–3) obtained using LS radiographs and the Osteoarthritis Research Society International atlas in the MT and in the cMF; pNPII, N-terminal propeptide of type II procollagen (ng/ml), sCPII, C-terminal propeptide of type II procollagen (ng/ml); pPGE₂, prostaglandin E₂ (pg/ml); ROC, receiver operator characteristic; sCOMP, cartilage oligomeric matrix protein (U/l); sCTXI, C-terminal telopeptide of type I collagen (ng/ml); sPIIANP, N-terminal propeptide of type IIA procollagen (ng/ml); sPIIINP, N-terminal propeptide type III procollagen (ng/ml); ThCtAB, mean thickness (averaged over the total area of subchondral bone (tAB) in the MT and in the cMF); uARGS, aggrecan ARGS neoepitope (ng/mg creatinine): p15HETE, hydroxyeicosatetraenoic acid (pg/ml); uCTXII, C-terminal telopeptide of type II collagen (ng/mmol creatinine); uOsteop, osteopontin neoepitope peptide (ng/mg creatinine): p3-NT, plasma 3-nitrotyrosine (pg/ml); uTIIINE, type III collagen neoepitope (ng/mg creatinine); uTIINE, type II collagen neoepitope (ng/mmol creatinine); uTINE, type I collagen neoepitope peptides (ng/mg creatinine); WOMAC, Western Ontario and McMaster Universities scores: ranges are 0–20 for pain, 0–8 for stiffness and 0–68 for function (with higher values indicating more pain, more stiffness and worse function).